If you usually picture "lettuce" as something that's cling-wrapped, roughly the shape and size of a softball, and a bit on the bland side, your eyes (and taste buds) are about to be opened. There are so many types, shapes, colors, and even flavors among lettuces, and some are easier to grow in the home garden than others.
Types of Lettuce
In general, there are four main types of lettuce: loose leaf, butterhead, crisphead, romaine, and batavian. There are, of course, other greens such as arugula, mizuna, and cress, but those aren't technically lettuces. Each type of lettuce has its own growth habit, texture, flavor, and ease of growth (as well as its own heat-tolerance, which is important for gardeners to know.)
You can harvest any lettuce either as baby leaves or even microgreens or let them grow to full size.
Loose Leaf Lettuce
Loose leaf lettuce forms loose heads of lettuce that are easy to harvest a leaf at a time. Many of these are often also referred to as "cut and come again" types, since you can simply harvest the outer leaves or largest leaves and allow the rest of the plant to keep growing. You can also just snip an entire section of these plants a couple inches above the soil, and you'll likely get at least one more harvest of baby greens or even microgreens that way.
Looseleaf lettuce is also a great container gardening option. It grows well in pots, window boxes, or just about any other type of container. Just make sure that whatever container you choose provides at least six inches of soil depth.
If you want looseleaf lettuce to grow to its full size and form heads, it takes about 40 to 50 days. But you can generally expect to be able to get a harvest of lettuce leaves a couple of weeks after planting.
Some great-tasting, attractive varieties of loose leaf lettuce include:
- 'Salad Bowl' forms pretty rosettes of delicate lime green colored leaves. It's a good, heat-tolerant variety, so this is a good one to grow if you have short cool springs and want to be able to extend your lettuce-growing time into the summer.
- 'Four Seasons' is a very cold-tolerant, pretty, heirloom variety. Its red leaves are tinged yellow along the veins and lower parts of the leaves, making it very pretty in a salad. Because it's so cold-tolerant, this is a good one for the very early spring or late fall garden, because it can withstand a cold snap that might spell the end for other lettuces.
- 'Oakleaf' is available in both red and green varieties and its leaves resemble... you guessed it! -- oak leaves. The color and shape of this lettuce makes it a lovely addition to a salad, and it can easily be harvested both as baby greens or fully-grown leaves.
- 'Black Seeded Simpson' is a must-have if you want to be able to grow lettuce into the summer. This green, slightly frilly-looking variety has outstanding heat tolerance and a good, mild flavor.
Butterhead lettuce, also called Boston or bibb lettuce, forms loose, flat, almost floral-looking heads. This type of lettuce is perfect if you enjoy making lettuce wraps, because the leaves hold up well to fillings. This is also a good salad lettuce and holds up well with other salad ingredients and dressings, keeping a nice, crisp texture. The inner leaves blanch a bit, inside the outer leaves, so they end up being lighter in color than the outer leaves.
While lettuce can be difficult to grow in hot weather, some varieties of butterhead lettuce known as "summer Bibb" can withstand heat longer than others, and these are definitely worth looking into to keep your lettuce crop going longer.
Butterhead lettuce plants should ideally be spaced 12 inches apart (though there are miniature or "baby Bibb" varieties which are bred to form smaller heads - these can be planted closer together.)
In general, butterhead lettuces are ready to harvest in 55 - 75 days.
If you're interested in growing butterhead lettuce, here are a few varieties to try:
- 'Buttercrunch' is a heat-tolerant, dark green variety that forms neat, round rosettes, sometimes tinged with red at the edges of the leaves.
- 'Bibb' forms bright green, buttery leaves in loose rosettes. Developed in the late 1800s, this variety wasn't commonly grown until the 1960s, when it surged in popularity. It's now one of the most common types of butterhead lettuces grown.
- 'Boston' forms loose heads of dark green leaves that form nice little cup or bowl shapes, making them perfect for wraps or as little bowls for fillings.
- 'Kragran Summer' is a tasty, bolt-resistant variety that forms loose heads of medium-green leaves. This is a good midsummer variety, since it withstands the heat better than other butterhead lettuces.
Crisphead (often referred to as Iceberg lettuce because that was the most common variety grown) is the most commonly sold type of lettuce in the United States. It forms crisp, tight heads and has a crunchy texture that is lovely in salads, but the drawback is that this is one of the most difficult lettuces to grow in the home garden.
If the weather in your area reaches 70 degrees Fahrenheit or warmer for more than a couple of days in a row, crisphead lettuces will quickly bolt and become bitter and inedible.
You can try to mitigate this by growing your lettuce in an area that is in shade during the hottest part of the day, but even then, nature will eventually take its course.
Crisphead lettuces take anywhere from 50 to 90 days from planting to harvest, depending on which variety you're growing.
Some crisphead lettuce varieties to try include:
- 'Ithaca' forms tightly-wrapped heads that reach about six inches in diameter. This variety is a bit more heat tolerant than many crispheads, and might do well if you can give it a bit of afternoon shade or protect it with a shade cloth.
- 'Iceberg' - this is the variety that became the status quo for American lettuces through the 1900s. Crispy, light green, but very quick-bolting, so this would be a decent variety for those gardeners with short, cool summers.
- 'Great Lakes' is a heat-tolerant crisphead lettuce that forms crisp, large, solid heads. If you want to try to grow crisphead lettuce into the summer, this is the variety to try.
- 'Imperial' is a reliable variety that forms dense dark green heads.
Romaine (also known as cos lettuce) is also a head-forming type, but it forms tighter heads than butterhead lettuces and taller heads than iceberg. It'll also withstand warm temperatures for a bit longer than crisphead lettuce will. It also tends to be a bit more flavorful than crisphead lettuce, and it's also a good type to grow if you enjoy making and eating lettuce wraps.
There are green romaine varieties, as well as some that have lovely purple or reddish tinges to the leaves. You can grow romaine lettuce in containers; just be sure that whatever you plant in is at least eight inches deep.
Romaine is usually ready to harvest in about 70 to 75 days, though of course you can harvest baby romaine heads sooner than that.
Some terrific romaine lettuce varieties to grow in your garden include:
- 'Rouge D'Hiver,' which has leaves that have a bronze to deep red hue that looks gorgeous in both the garden and on the plate
- 'Jericho' is an heirloom variety with deep green, long, narrow leaves that is more heat-tolerant than many romaine varieties
- 'Paris White Cos' has leaves that are white closer to the root and become deep green toward the outer edge of the leaves. The inner leaves are all white, making this very pretty in a salad.
- 'Freckles' is a gorgeous lettuce that has deep green leaves with deep red spots all along them. Aside from being pretty, 'Freckles' has a very crisp texture and works well as either an early-season or late-season lettuce.
If you enjoy the crunchy texture of crisphead lettuce and the frilly look of leaf lettuces, but also need to grow lettuce that can withstand a bit of heat, you might want to look into batavian types. These lettuces form loose, open heads of frilly leaves, usually green or red. They taste similar to romaine lettuce, with a slightly bitter bite.
You can grow batavian lettuce in containers, as long as the containers are at least 8 inches deep. As a bonus, unlike most lettuce types, batavian lettuce seeds will germinate even in warm weather, so this is a good type to plant in summer as a fall crop.
Batavian lettuce is usually ready to harvest in about 50 days.
Some batavian lettuce varieties to try include:
- 'Nevada' has dense, green heads and crisp leaves, with a mild flavor.
- 'Loma' has glossy, dark green leaves with pretty, frilled edges. The leaves are firm and crisp, and this variety is fairly heat-tolerant as well.
- 'Cardinale' is a very pretty lettuce. It has leaves that go from green, to rose-colored, to bronze at the edges of the leaves, which makes each head of 'Cardinale' look like a flower. The leaves are crunchy and thick, so they're a good option if you like to mix warm and cold ingredients or dressings for your salads, since it can stand up to heftier accompaniments.
- 'Merlot' is a gorgeous, ruby-colored lettuce with an upright growth pattern and long, oval-shaped leaves. It's a great option both to harvest as baby leaves for salads, or to wait and harvest as full heads, at which time its leaves will be much crisper.
How to Grow Lettuce
Lettuce is a cool-weather crop. In hot climates, they cannot be grown in the summer. Heat makes the plants bolt, which means they send up a flower stalk in an attempt to produce seed before the plant dies. Once this happens, the plant gets tall and spindly-looking, and the taste will quickly become very bitter. At this point, all you can do is pull the plant and sow or transplant something else.
Lettuce doesn't need full sun, and growing it in shade gives it some protection from the heat. Many gardeners plant it between slow-maturing crops like cabbage or peppers and harvest it before the slower crops need the space. It thrives in the shade cast by corn, pole beans, staked tomatoes, or other tall crops.
Even moisture is very important for lettuce, since the roots are shallow and dry out quickly. Mulching helps retain moisture.
Avoid overhead watering; wet leaves are vulnerable to mildew and leaf rot. Soak the soil instead.
Soil and Fertilization
Lettuce needs a rich soil, with a high nitrogen level to promote leaf growth. Soil should have a light, moisture-retentive texture. The ideal pH is between 6.0 and 7.0.
Fertilizing weekly with a weak solution of a balanced organic fertilizer will keep your lettuce growing strong, as long as the weather doesn't get too hot. Top-dressing with a nitrogen-rich fertilizer like blood meal, cottonseed meal, or a fish emulsion helps to sustain the fast, steady growth that lettuce needs. Manure or compost tea is also good.
You can have fresh lettuce for salads by sowing seeds every two weeks all season. Plant heat-resistant varieties in the summer and cold-resistant varieties in the spring and fall.
For very early crops, you can start lettuce seeds indoors.
- Sow seed eight weeks before the last expected frost date.
- Keep the flats below 70 degrees and evenly moist.
- When the plants are three or four inches tall, harden them off for a few days and set them out in the garden.
- Space them about a foot apart, depending on the variety.
Sow lettuce seeds in the garden as soon as the soil can be worked. They can be sown in rows or blocks, but try to distribute seed as thinly as possible. Mixing the tiny lettuce seeds with a little sand or buying pelleted seed makes this easier.
Wet the soil thoroughly. Scatter the seed, and cover it with a fine sprinkling of soil. Keep the seedbed moist.
Lettuces are harvested in different ways, depending on the type.
- Pick individual leaves of loose leaf lettuce.
- You can pick the outer leaves of butterheads while leaving the inner leaves to grow, or you can cut off the entire head about an inch above the soil and let a new head grow from the root.
- Heading lettuce, such as batavian, romaine, and crisphead, is usually pulled up whole, but the outer leaves can be picked separately.
Problems and Pests
Few pests bother lettuce, although cutworms and slugs can be annoying. Leaf rot is caused by several kinds of soil-borne fungi.
Mulching, rotating crops, and clearing away all debris promptly are preventative measures. So-called 'tip burn' is a normal result of hot weather and can be minimized by providing moisture and shade.
Grow Your Own Flavorful, Beautiful Lettuce
Lettuce is so much more than a sandwich topping or the backdrop for tastier salad ingredients. By growing a few different types, you'll experience a variety of flavors and the pretty colors and shapes that go with them.